fluid layouts started

Natours/starter/sass/base/_base.scss

@@ -0,0 +1,16 @@
+*,
+::after,
+::before {
+    margin: 0;
+    padding: 0;
+    box-sizing: inherit;
+}
+
+html {
+    font-size: 62.5%;
+}
+
+body {
+    padding: 3rem;
+    box-sizing: border-box;
+}